Predetermined torque release socket wrench



Dec. 5, 1961 H. c. sTUMPF PREDETERMINED ToRQUE RELEASE socxET WRENCH Filed Aug. zo, 1960 ATTORNEY States Patent @fune 3,011,372 Patented Dec. 5, 1951 3,011,372 l PREDETERMINED TORQUE YRELEASE SOCKET WRENCH Howard C. Stumpf, 9 Whittemnre Terrace, Wakefield, Mass. Filed Aug. 30, 1960, Ser. No. 52,993 8 Claims. (Cl. til-52.4)

The present invention relates generally to an improved wrench, and in particular it relates to an improved wrenchv of the torqueor pressure-controlled type.

In applying nuts or threaded caps to threaded bolts, studs or the like, it is often necessary or desirable that the pressure of the nut or cap, and hence the tightening torque applied thereto, be closely controlled. Frequently, in mass production operations, alarge number of nuts are applied to threaded Shanks of equal lengths, and it is essential that the tightening torque applied thereto be uniform to avoid unequal pressures and other detrimental effects. Heretofore, torque-measuring. wrenches or controlled torque wrenches of the slipping or disengaging type have been employed in the above circumstances. However, the use of such wrenches possesses many drawbacks and disadvantages. The employment of the torque-measuring type of wrench generally requires constant visual observance of the Wrench dial, which is not only inconvenient but often extremely diiiicult. The use of the slipping or disengaging type of torque is generally limited to motor driven wrenches and, like the torque measuring wrench, is usually a clumsy and awkward device. When the latter wrench is hand-driven, it often leads to bruised knuckles and other injuries as a result of the slipping of the drive lever or handle. It is apparent from the above that the use of the conventional torque-measuring or torque-controlled wrenches leaves much to be desired.

It is thus a principal object of the present invention to provide an improved wrench.

Another object of the present invention is to provide an improved wrench of the torque-l or pressure-controlled type Still another object of the present invention is to provide an improved torque-controlled socket wrench which -rnay be employed in areas difficult of access` Y A further object of the present invention is to provide an improved torque-controlled socket Wrench which may be easily and accurately employed, even by unskilled operators. f

Still a further object of the present invention is to provide an improved torque-controlled socket wrench which releasably engages the core dome of lock nuts of various sizes and constructions.

Another object of the present invention is to provide an improved torque-controlled socket wrench which produces an audible signal as an indication of the proper tightening of the applied nut as previously determined.

A further object of the present invention is to provide an improved wrench of the above nature characterized by its ruggedness, simplicity, and low cost.

Other objects of the present invention will in part be specifically pointed out and in part apparent from the reading of the following description taken in conjunction with the accompanying drawings, wherein:

FIGURE l is an exploded perspective View of a wrench constructed according to and embodying the present invention; and i FIGURE 2 is a longitudinal cross-sectional view of the assembled wrench illustrated as applied to the tightening of a nut.

In a sense, the present invention contemplates the provision of an improved wrench of the character described, comprising a body member having a longitudinally extending socket of polygonal transverse cross-section formed in the leading end thereof, a longitudinally adjustable core member, an abutment member carried by said core member and longitudinally movable thereon between an advanced position toward the open end of said socket and a retracted position rearwardly thereof, and having an abutment face confronting said open end of said socket, and' spring means urging said abutment member toward its advanced position.

In accordance with a preferred embodiment of the present invention, the body member has formed therein, in addition to said socket, a cylindrical well trailing and communicating with the socket. Also formed in the body member in communication with the aforesaid well is a tapped longitudinal bore, the trailing end of which terminates in a socket of square cross-section communicating with the end of the body member and permitting the reception of a suitable tool for manipulating the wrench.

The core member includes a trailing threaded shank which engages the tapped longitudinal bore and is provided at its end with a slot for the reception of a screw driver to permit the longitudinal adjustment of the core member. The abutment member is defined by a piston having a front wall confronting the open end of the socket and a trailing skirt which slidably engages the leading end-of the core member. A pin is carried by the skirt and registers with a longitudinal depression or recess in the core member to limit the movement of the piston between its advanced and retracted positions, and a helical compression spring nests in a well at the leading end of the core member and bears against the front wall of the piston to urge the piston to its advanced position. A nut-engaging sleeve has its trailing end slidably nesting in the body member cylindrical well and its leading end located in and spaced from the wall of the socket. Longitudinal slots are formed in the leading end of the sleeve to delineate resilient fingers which are adapted to engage the domed portion of a lock nut.

In order to provide an audible indication of the retraction of the abutment piston, an opening is formed in the piston which registers with a ball which is spring urged outwardly when the piston is in its retracted position. A threaded lock pin engages the trailing end of the body tapped bore to permit the locking of the core -in any selecte-d longitudinal position.

Referring now to the drawings which illustrate a preferred embodiment of the present invention reference numeral 10 generally designates the improved tool which comprises a body member 11 which is of longitudinally extending cylindrical configuration and is preferably lformed of steel or other suitable metal. Formed in the leading end of body member 11 is a well 12 extending for approximately half the length of said body member 11, and including a front nut engaging socket 13, having a surface of substantially polygonal cross-section to permit a slip-proof engagement with an appropriately sized nut in the usual manner. Trailing socket 13 and separated therefrom by an annular shoulder 14 is a cylindrical well 16 terminating in a centrally apertured base 17.

Formed inthe trailing end of body member l1 is a tool receiving socket 18 of substantially square transverse cross-section, a side wall of which is provided with a radially extended tapped opening 19. A longitudinally extending tapped axial bore 20 extends between base 17 of well 16 and the base of the tool receiving socket 18. In order to facilitate the manipulation of the wrench, there is provided an elongated handle member 21, having a threaded stub shank 22 which is adapted to engage tapped opening 19.

' A nut-holding member 23 of tubular configurationhas its trailing end tightly nestedl in well section 16, withy its forward end projecting into the socket 13, the front thereof being disposed rearwardly of the leading edge of socket 13. A plurality of circumferentially spaced, longitudinally extending slots 24 are formed in the leading end of member 23 and delineate a correspondingfplurality of resilent iingers or clamps 26 adapted to releasably engage the crown or collar 27 of alock nut N.

A core-dening elongated rod 2S is provided with la threaded rear shank 29 engaging tapped bore 2t) in body il, and has a transverse slot 30 in its rear end face for the reception of a screw driver to permit the longitudinal adjustment of said core 28 relative to body member il. Formed on the leading peripheral surface of core 28 is a pair of longitudinally extending and aligned front and rear iiat or uniformly depressed areas or recesses 32. and 33, `arranged end-to-end and separated by an intervening wall 34. A longitudinally extending well 36 is formed in the front end of core 28, and a radially extending well 37, is formed in core member 2S directly behind and separated from well 36. A threaded lock pin 33 registers with tapped bore 20 in the body member and trails threaded shank 29, to permit the releasable locking of core 28 in preselected positions in said body member 11.

The abutment member is delined -by a piston 39 which includes a front abutment wall 4l) and a rearwardly projecting cylindrical skirt 41 which surrounds and slidably engages core 28. A pin 42 is provided extending across skirt 43. and engaging oppositely disposed apertures 43 formed in skirt 4l, said pin registering with iiat 33 to limit the movement of piston 39 between an advanced and a retracted position as determined by the pin 42 abutting the leading and trailing walls 34 and 34a bordering the front and rear of iiat 33. A spiral compression spring 44 nests in well 36 and bears upon the rear face of the piston wall 4t) thereby normally to urge piston 39 to its advanced position.

In order to provide an audible signal or indication when piston 39 is moved to its retracted position, or the position at which the desired torque is achieved, a circumferentially extending slot 46 is formed in piston skirt 41 approximately intermediate the ends thereof. A steel ball 47 registers with the transversely extending well 37 in core 28, and is normally urged outwardly by a spiral compression spring 43 entrapped between the confronting face of Iball 47 and the baseof well 37. When the piston 39 is in the forward position, ball 47 bears against the inner face of piston skirt 4l, spaced away from the inner face of tubular member 23. Upon movement of the piston from its advanced to its retracted position, a click is produced by movement of ball 47 striking the wall of the tubular member 23 passing through slot 46, as piston 39 reaches substantially the retracted position shown in FIGURE 2.

Considering now the operation and application of the improved wrench of the present invention, it is first adjusted to achieve thetorque desired by removing threaded lock pin 3S and retracting core 28, applying the wrench to a nut N screwed onto a threaded shank S in a standard or normal set-up at the desired torque. Core 28 is then advanced manually by rotating it within body member 11 by means of a screw driver engaging cross-slot 30 until piston 39 is brought to its fully retracted position by the extension of shank S. It will be understood that, -as core 28 is advanced, piston 39 is borne forward with it by reason o-f the engagement of pin 42 trapped across core flat 33. Piston 39, under the inuence of spring 44, will be in its advanced position. The core is thereupon locked in positon by replacing and tightening threaded lock pin 38.

Thereafter, in applying and tightening nuts, as N, shown as of the lock-nut type, the latter are rst brought into registry with socket 13, the crown portions of the nut 4being engaged by lingers 26, the leading edges of which abut against the top of the nut body. The particular nut N is then engaged with the bolt or stud threaded shank and rotated by wrench l0, employing handle 21 or a suitable tooly engaging socket i3, until a click is heard yby reason of ball 47 registering with slot 46 in the retracted piston 39 striking member 23. The click is an indication of the proper tightening of nut N, further tightening of which is prevented since piston 39, whose front wall abuts the end of the shank S, has reached the limit of its rearward movement.

The wrench is then disengaged from the tightened nut, whereupon the biasing of spring 44 will return piston 39 to its advanced posi-tion and disengage ball 47 from member 23, at which time the wrench will be ready for tightening the next nut.

While there has been illustrated and described hereinabove a preferred embodiment of the present invention, it will be apparent that numerous alterations, additions and omissions may be made without departing from the spirit thereof, as set forth in the appendedV claims.

I claim:

l. An improved wrench of vthe character described comprising a body member having a longitudinally extending socket of polygonal transverse cross-section formed in the leading end thereof, a longitudinally adjustable core member located in said body member, an abutment member carried by said core member and longitudinally movable thereon between an advance position toward the end open end of said socket and a retracted position, and having an abutment face confronting said open end of said socket, and spring means urging said abutment member toward its advance position.

2. An improved wrench of the character described comprising a body member having a longitudinally extending socket of polygonal transverse cross-section formed in the leading end thereof, said body member having a longitudinally extending tapped bore formed therein communicating with said socket, aV longitudinally extending core member having a threaded trailing shank engaging said tapped bore, and having a leading section projecting toward said socket, an abutment member including a front wall directed toward the front of said socket and a trailing section slidably engaging said core member leading section, means limiting the movement of said abutment member relative to said core member between an advanced and retracted position, and spring means urging said abutment member toward its advance position.

3. An improved wrench of the character described comprising a body member having a longitudinally extending socket of polygonal transverse cross-section formed in the leading end thereof, said body member having a longitudinally extending tapped bore formed therein communicating with said socket, a longitudinally extending core member having a threaded trailing shank engaging said tapped bore, and having a leading section projecting toward said socket, a hollow cylindrical piston including a front wall directed toward said socket and a trailing skirt slidably registering with said core member leading section, means limiting the longitudinal movement of said piston in said core member between an advanced and retracted position, and spring means urging said piston toward its advanced position.

4. A Wrench in accordance with claim 3, wherein said core member has a well `formed in Vthe leading end thereof and said spring means is defined by a compression spring nesting in said well and bearing upon the rear face of said piston front wall.

5. A wrench in accordance with claim 3, including means emitting an audiblesignal upon said piston moving to its retracted position.

6. A wrench in accordance with claim 5, wherein said signal means includes a radially movable element carried by said core, spring-urged outwardly, said piston having an opening formed in itsl skirt, which opening registers with said movable element when said piston is in its References Cited in the file Aof this patent retracted 11081110? UNITED STATES PATENTS 2,887,921 Llvermont May 26, 1959 threaded lock bolt registering with said threaded bore and in abutting said core member. 

